Theres probably a hack possible where you disable the battery voltage monitoring. Probably seeing an open circuit on the battery terminals makes it think that battery is completely dead and triggers an emergency power off.

The other alternative would be to connect 4 volts to the battery terminals so it looks like a battery is there.

I think this is where it checks for too low of a voltage. But I'm not certain, you might need to experiment. The only players I've tried have refused to even boot without a battery installed, so I have no experience here.

Theres probably a hack possible where you disable the battery voltage monitoring. Probably seeing an open circuit on the battery terminals makes it think that battery is completely dead and triggers an emergency power off.

The other alternative would be to connect 4 volts to the battery terminals so it looks like a battery is there.

Thanks for the tips. While you folks were typing, I was on the same track.

Here's an old Axim X51v cell double-side stick taped to the back. I snipped off the plastic terminal protection grid and soldered up the +, T, and - pads to red, blue, and black connections on the PCB of the protection circuit on the cell. I cut a slot in the bottom of the back cover to pass the wires.

For some reason, it shows that it's charging but the battery level never does. So I pulled off the Kapton tape and use the charging cradle for the battery instead.